Safety device for a skilift

ABSTRACT

The safety device permits the detection of a crossing of the end of a skilift track, and it includes a rope stretched between two fixed points, the inflexion of this rope constituting the signal that the limit has been passed. The inflexion of the rope is detected by the pivoting of winding drums on which are wound the ends of the rope.

United States Patent 1191 Brian Oct. 29, 1974 SAFETY DEVICE FOR A SKILIFT [56] References Cited [75] Inventor: Rene Brian, St. Nazaire Les Eymes, UNITED STATES PATENTS France 3,209,703 lO/l965 Brebner 104/l73 ST [73] Assignee: Pomagalski S.A., Fontaine, France Primary Examiner Drayton E. Hoffman [22] Filed: Nov. 21, 1972 Attorney, Agent, or FirmStevens, Davis, Miller & 21 Appl. No: 308,584 Mosh [57] ABSTRACT [30] Foreign Application Priority Data Dec. 8, 1971 France 7144144 The Safety device Permits the detection of a Crossing of the end of a skilift track, and it includes a rope 52 US. Cl. ..104/'17"3, 104/178, 104/179 Stretched between two fixed Points, the ihfleXiOh 0f [51 1m. (:1 B6lb 11/02 P constituting the Sight" that the hmh has been 58 Field of Search 104 173 R, 173 ST, 178, passed- The ihflexhm of the rope is detected by the pivoting of winding drums on which are wound the ends of the rope.

3 Claims, 4 Drawing Figures SAFETY DEVICE FOR A SKILIFT The invention relates to a safety device, in particular for the end of a skilift track for purposes of signalling and/or bringing about the stopping of the skilift should a skier pass beyond the end of the track.

Safety devices are known which bring about the stopping of the lift when a skier, towed by the towhanger, goes beyond a predetermined limit, in order to prevent the towing of the skier around the terminal sheave of the skilift, and possibly in the downhill direction. The systems known necessitate a personal intervention to reset the device and so permit the restarting of the lift, and thus cannot be used in the case of an installation run by a single operator, who is usually at the departure terminal.

The object of the present invention is to remedy this disadvantage and to permit the realizing of a particularly simple safety system, functioning automatically, and reliable.

According to the invention, a barrier, installed at the end of the track, is advantageously constituted by a single wire or rope strained between two posts, and capable of extending in length, either by reason of its own elasticity or by means of winding reels. When a skier comes into contact with the rope, this is dragged forward by the movement of the skier and takes the form of a V, by extending elastically. A sensor that is sensitive to a change in the direction of the rope, or to its extension or to an analogous modification, brings about the signalling of the said crossing, and possibly the automatic stopping of the skilift.

Another object of the invention is the realizing of a safety device not affected by snowfalls and easily adapted to the depth of the snow. The height of the rope is adapted to the level of the snow.

Another object of the invention is to permit an appreciable extension of the barrier rope and avoid any friction on the body of the skier in contact.

According to an embodiment of the invention, two reels are used on each of which is wound one of the ends of the rope, so as to make available a considerable stock of rope, and ensure a certain stopping of the lift, whilst avoiding any slipping of the rope on the skier. A sensor is associated with each reel, electrically connected in series with the safety circuit of the lift, so as to bring about the stopping of the lift on the opening of one of the contacts associated with the sensors.

The safety device according to the invention may of course be used for the detection of the crossing of any limit, for example that of a prohibited zone. The rope may be installed in a broken line demarcating the prohibited zone the crossing of which must be signalized or must cause the stopping of the installation.

Other advantages and objects will readily become apparent upon reading the following description taken in conjunction with the drawings, in which:

FIG. 1 is a schematic plan view of the end of a skilift equipped with an end-of-track safety device according to the invention;

FIG. 2 is a fragmentary view in elevation, showing partly broken away the fixing system of the rope and associated reel;

FIG. 3 is a view analogous with that of FIG. 1, illustrating a modified type of the installation;

FIG. 4 is a view analogous with that of FIG. 2, showing a variation of the sensor.

In FIG. 1 an overhead cable 10, of a transport installation of the skilift type l2passes around a terminal sheave 14 at the end of the track on which are towed the skiers. In front of the terminal sheave 14, in relation to the direction of travel of cable 10, shown by an arrow in the figure is installed a safety device 16 defining the end of the towing track. The towed skiers generally leave or release the towhanger (not shown) before reaching the safety device, which thus does not intervene under normal working conditions. Safety device 16 detects, on the contrary, the passing of a skier caught on the towhanger, for example, and causes the stopping of the skilift.

Safety device 16 has a rope or wire 18 stretched between two posts 20, 22 on each side of the trajectory of cable 10, and preferably perpendicular to the trajectory. Each end of the rope 18 is wound on a reel 24 of a winder 26, 28 the case of which is fitted so as to pivot on a vertical spindle 30, fixed on the post 20, 22 respectively (see FIG. 2). Winders 26, 28 are both provided with an elastic return system, for example a spiral spring (not shown) tending to wind rope 18 on reels 24. It is easily seen that the rope 18 is thus stretched be tween posts 20, 22 and can in case of being reached or engaged by a skier be deviated to reach the position in the form of a V, shown by a dotted line in FIG. 1, without preventing or particularly hindering the movement of the skier. The fixing of the winders 26, 28 respectively on posts 20, 22 is advantageously effected by means of a clamp 32 designed to slide on the pole, and with a locking screw 34 to permit the adjustment of the height of the rope in case of variation of the thickness of the layer of snow.

With each winder 26, 28 is associated a detector, shown schematically in FIG. 1 by an electrical contact respectively 36, 38 actuated by a cam or trigger respectively 40, 42 fixed to winder 26, 28. When the rope is in the rest position contacts 36, 38 are in the closed position and are electrically connected in series with the skilift safetey line. The safety line (not shown) extends over the whole length of the skilift and is connected to a signal and control device installed in the drive termi nal of the installation. In a manner in itself well known, cable derailment detectors or other safety devices are inserted in the safety line and the signal device permits the location of the fault. The interruption of the safety line, for example by the opening of one of the switches of a detector, brings about the automatic stopping of the installation.

Cams 40, 42, carried by winders 26, 28, are so designed as to open contacts 36, 38 in the case of the pivoting of winders 26, 28 corresponding with the inflexion or movement of rope 18 towards the position indicated by a dotted line in FIG. I. It is easily seen that once a skier is freed from the rope this automatically returns to the taut rest position under the action of winders 26, 28, the corresponding pivoting of the winders freeing contacts 36, 38 which close automatically.

Downwards safety device 16, in relation to the direction of movement of the cable, for example after sheave 14 has been passed, is a second safety device 44, consisting for example of a gate 46, the pivoting of which causes the opening of a detector or contact 48, bringing about the stopping of the lift and necessitating an on-the-spot intervention.

The safety device described functions in the following manner:

Skiers towed by overhead cable let go the towhanger before reaching the end of the track indicated, apart from other means by rope 18, which bars the track transversely. The freed towhangers are retracted by means of their elastic system and normally pass above rope 18. A skier who accidentally remains with his towhanger continues his travel and when he crosses the end of the track drags rope 18, which unwinds from the reels 24 taking a bent or inclined position, shown by a dotted line in H6. 1. The inclination of the two ends of the rope brings about that of winders 26, 28, cams 40, 42 of which engage the triggers opening contacts 36, 38. When one of these contacts is opened the motor (not shown) of the installation is automatically stopped as a result of the interruption of the safety line. A signal device of some kind indicates the functioning of the end-of-track detector 16, and while the lift is stopped the skier may free himself from the towhanger. On leaving the track he frees rope l8 and the winders, under the action of their springs, automatically return the rope to its taut position in which winders 26, 28 permit the re-closing of contacts 36, 38 thus renewing the continuity of the safety line. The skilift supervisor is advised of this return to its position of the end of track safety device by the disappearance of the alarm signal, and he can start the installation once more, preferably at reduced speed.

The safety of the installation is increased by the presence of the second detector 44, the object of which is to bring the installation to a halt in the unlikely case of inefficient functioning of barrier 18. A skier could free himself from barrier 18 before freeing himself from the towhanger and the supervisor, thinking that the incident has been eliminated, could start the lift again thus dragging the skier once more. After passing round sheave 14 the skier comes into contact with gate 46 and bring about through the opening of contact 48 the stopping of the installation thus necessitating an on-thespot intervention. Thus, as mentioned above, it is preferable to run the installation at low speed for a period corresponding with the distance separating barrier 18 from gate 46. The second safety device 44 is of course in no way indispensable, and the same function may be realized in any other manner, for example with a simple wire, the breaking of which would bring the installation to a stop, or by a barrier system of the type described above.

The system with two winders 26, 28, illustrated in FIG. 1, makes it possible to avoid any rubbing of rope 18 on the skier, as it is unwound from the two winders. A good length of rope 18 is available, permitting a considerable deflection and thus the certain stopping of the installation. It is of course well understood that the barrier could be devised in some other manner, for example using a net or articulated components and that the stretching of the rope could result from its own elasticity or from some other elastic system well known in itself. The actuating of detectors 36, 38 may be different, in particular by means of a system acted on directly by the rope 18 on reaching an inclined position, or by some analogous system.

FIG. 3 illustrates an end of track device 16, analogous with that of FIG. 1, combined with a device 17 delimiting a prohibited zone. The same reference numbers designate parts identical with or analogous with those of FIG. 1. Rope l8 strained across the trajectory of overhead cable 10 passes over an idler wheel and extends over a trajectory parallel with that of cable 10 before being fixed to post 20. Part 52 of rope l8 strained between idler wheel 50 and post 20 delimits the prohibited zone between the uphill and downhill sides of overhead cable 10, and prevents skiers from approaching the inner part of the skilift, that is to say towards the left in FIG. 3.

It is easily seen that the crossing over of the end of the track by a skier causes the pivoting of winder 28 associated with the post 22 and thus the opening of contact 38 causing in the manner described above the stopping of the skilift. Once the skier has been freed barrier 18 automatically returns to its original position. During this operation section 52 of the rope has remained in alignment but winder 26 has contributed to the extension of rope 18. When section 52 between idler wheel 50 and post 20 is engaged, winder 26 pivots around post 20 and opens safety contact 36, causing the stopping of the installation. The same device thus provides safety at the end of the track and the delimitation of a prohibited zone.

The detection of the action of rope 18 may be effected in some other manner, for example in that shown in FIG. 4, by the opening of a contact 54 on the rotation of reel 24 of the winder. The rotation of reel 24 is detected by a crank 56 which is an easy fit on spindle 58 of reel 24. A rotation of reel 24 in the clockwise direction in FIG. 4, corresponding to the unwinding of rope 18, moves by friction crank 56, which strikes the trigger of contact 54 and causes its opening. Contact 54 is inserted in the usual way and brings about the stopping of the skilift. The crank 56 contact 54 system is so devised as to remain in the open position as long as no unwinding of the rope 18 has commenced. The corresponding rotation in the opposite direction of spindle 58 moves crank 56 in the opposite direction and against a pawl 60 on the casing of the winder 26 permitting the closing of contact 54. The system according to FIG. 4 is sensitive to any unwinding of rope 18, that is to say to any lengthening of the rope which may be extended following a polygonal contour defined by idler wheels or over long distances. The unwinding of rope 18 may also be detected by a device actuated directly by rope 18, for example by friction or by an extra thickness of part of the rope coming into contact with any kind of control system. The lengthening of rope 18 is accompanied by an increase in its tension, which may be detected in a usual manner, for instance by an extensometer inserted in the rope. This increase in tension may serve as a signal that the safety barrier has functioned.

What is claimed is:

l. A skilift, said skilift comprising:

a. a tow track including a tow track end;

b. a safety device for protecting skiers, said safety device extending transversely of said tow track proximate said tow track end to detect crossing of said end by a skier, said safety device comprising:

i. a pair of anchoring points, one of said points disposed on each side of said track;

ii. a rope attached to and normally elastically stretched between said points across said tow track, whereby engagement of said rope by a skier passing over said tow track end will anguspective one of said anchoring points.

3. The skilift according to claim 2 wherein said safety device further comprises fixing means for pivotally securing each said winding means to its respective anchor point, for pivoting about a vertical axis, the safety device further comprising means for detecting pivoting of said winding means. 

1. A skilift, said skilift comprising: a. a tow track including a tow track end; b. a safety device for protecting skiers, said safety device extending transversely of said tow track proximate said tow track end to detect crossing of said end by a skier, said safety device comprising: i. a pair of anchoring points, one of said points disposed on each side of said track; ii. a rope attached to and normally elastically stretched between said points across said tow track, whereby engagement of said rope by a skier passing over said tow track end will angularly displace said rope from its normal position into a V-shape; iii. means for detecting said angular displacement of said rope relative to said anchoring points thereby to effect a stopping of the skilift as long as said rope retains said V-shape.
 2. The skilift according to claim 1 wherein said safety device further comprises a pair of winding means for said rope, each of said winding means secured to a respective one of said anchoring points.
 3. The skilift according to claim 2 wherein said safety device further comprises fixing means for pivotally securing each said winding means to its respective anchor point, for pivoting about a vertical axis, the safety device further comprising means for detecting pivoting of said winding means. 